CHAP. vi. J DEEP-SEA DREDGING. 



ZOO 



of very characteristic pale grey Atlantic ooze. The 

 total weight brought up by the engine was 



2,000 fathoms, 2 i -Inch rope 4,000 Ibs. 



1,000 fathoms, 2-inch rope 1,500 



5, 500 Ibs. 



Weight of rope reduced to one-fourth in water = 1,375 Ibs. 



Dredge and bag 275 ,, 



Ooze brought up 168 



Weight attached 224 



2,042 Ibs. 



Much more experience will yet be necessary before 

 we can assure ourselves that we have devised the 

 dredge of the best form and weight for work in the 

 deep sea. I rather think that the dredges, 150 to 

 225 Ibs., which we have been in the habit of using, 

 are too heavy. In many instances we have had 

 evidence that the dredge, instead of falling gently 

 upon the surface and then gliding along and gather 

 ing the loose things in its path, has fallen upon its 

 mouth and dug into the tenacious mud, thereby 

 clogging itself, so as to admit but little more. I 

 mean to try the experiment of heavier weights and 

 lighter dredge-frames in the e Challenger,' and I 

 believe it will be an improvement. 



In many of our dredgings at all depths we found 

 that, while few objects of interest were brought up 

 within the dredge, many echinoderms, corals, and 

 sponges came to the surface sticking to the outside 

 of the dredge-bag, and even to the first few fathoms 

 of the dredge-rope. 



This suggested many expedients, and finally 



